circleci changes to meet the MOD-1227 goals with how ci runs

[chayim]

1. valgrind-general will now run on external PRs, but not internal unless we add the ci-test label.
2. gpu builds will now run on external PRs, but not internal unless we add the ci-test label.
3. Runs on integ branches (master and versioned) continue to run gpu builds as before

This involves moving the executing steps from the workflows to the commands section, then reusing them. As such the workflow is duplicated (with rule changes and a new name), but the commands moved.

[codecov]

Codecov Report

Merging #766 (3c52a56) into master (ffbf441) will decrease coverage by 0.20%.
The diff coverage is 65.17%.

@@            Coverage Diff             @@
##           master     #766      +/-   ##
==========================================
- Coverage   79.38%   79.17%   -0.21%     
==========================================
  Files          48       49       +1     
  Lines        7476     7651     +175     
==========================================
+ Hits         5935     6058     +123     
- Misses       1541     1593      +52     

Impacted Files	Coverage Δ
src/serialization/AOF/rai_aof_rewrite.c	0.00% <0.00%> (ø)
.../serialization/RDB/decoder/previous/v1/decode_v1.c	64.63% <ø> (ø)
...c/serialization/RDB/decoder/current/v2/decode_v2.c	67.87% <67.87%> (ø)
src/redisai.c	85.46% <100.00%> (+0.03%)	⬆️
src/serialization/RDB/decoder/decode_previous.c	75.00% <100.00%> (+8.33%)	⬆️
src/serialization/RDB/decoder/rai_rdb_decoder.c	100.00% <100.00%> (ø)
src/serialization/RDB/encoder/rai_rdb_encode.c	100.00% <100.00%> (ø)
src/serialization/RDB/encoder/v2/encode_v2.c	89.28% <100.00%> (ø)
src/execution/execution_contexts/modelRun_ctx.c	80.55% <0.00%> (+1.85%)	⬆️

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[chayim]

@DvirDukhan An interesting byproduct of this is that I (clearly) can't name the job, with the same name as during the non-PR run. This means that while we have GitHub rules requiring a passing gate for ci/circleci:build-and-test-gpu, in the forked context there's ci/circleci:build-and-test-gpu-for-forked-prs (etc).